AbstractWarm water of open ocean origin on the continental shelf of the Amundsen and Bellingshausen Seas causes the highest basal melt rates reported for Antarctic ice shelves with severe consequences for the ice shelf/ice sheet dynamics. Ice shelves fringing the broad continental shelf in the Weddell and Ross Seas melt at rates orders of magnitude smaller. However, simulations using coupled ice–ocean models forced with the atmospheric output of the HadCM3 SRES-A1B scenario run (CO2 concentration in the atmosphere reaches 700 ppmv by the year 2100 and stays at that level for an additional 100 years) show that the circulation in the southern Weddell Sea changes during the twenty-first century. Derivatives of Circumpolar Deep Water are directed southward underneath the Filchner–Ronne Ice Shelf, warming the cavity and dramatically increasing basal melting. To find out whether the open ocean will always continue to power the melting, the authors extend their simulations, applying twentieth-century atmospheric forcing, both alone and together with prescribed basal mass flux at the end of (or during) the SRES-A1B scenario run. The results identify a tipping point in the southern Weddell Sea: once warm water flushes the ice shelf cavity a positive meltwater feedback enhances the shelf circulation and the onshore transport of open ocean heat. The process is irreversible with a recurrence to twentieth-century atmospheric forcing and can only be halted through prescribing a return to twentieth-century basal melt rates. This finding might have strong implications for the stability of the Antarctic ice sheet.

It should be noted that this modeling exercise that revealed a future tipping point did not include new data captured during the 2018/2019 Weddell Sea Expidition: https://weddellseaexpedition.org/news/

The resulting paper, with information from Boaty McBoatface, showed intensified turbulent mixing, which may result in a much shortened timeline until melt/tipping point in this area.

Rapid mixing and exchange of deep-ocean waters in an abyssal boundary current

Alberto C. Naveira Garabato et. al.

AbstractThe overturning circulation of the global ocean is critically shaped by deep-ocean mixing, which transforms cold waters sinking at high latitudes into warmer, shallower waters. The effectiveness of mixing in driving this transformation is jointly set by two factors: the intensity of turbulence near topography and the rate at which well-mixed boundary waters are exchanged with the stratified ocean interior. Here, we use innovative observations of a major branch of the overturning circulation—an abyssal boundary current in the Southern Ocean—to identify a previously undocumented mixing mechanism, by which deep-ocean waters are efficiently laundered through intensified near-boundary turbulence and boundary–interior exchange. The linchpin of the mechanism is the generation of submesoscale dynamical instabilities by the flow of deep-ocean waters along a steep topographic boundary. As the conditions conducive to this mode of mixing are common to many abyssal boundary currents, our findings highlight an imperative for its representation in models of oceanic overturning.

While some may say that the record breaking temperatures in many parts of Alaska just represent climate variability; I believe that such heat waves are currently accelerating positive feedback mechanisms such are increasing wildfires, in Alaska:

Title: "90-degree heat stifles Anchorage for first time in its history as sweltering heat wave grips Alaska"

The linked reference (& two following associated linked articles) discuss findings from the Grace satellite w.r.t. the Antarctica. Among other things, this research can help to quantity how fast West Antarctica will rebound as it continues to lose ice mass:

Abstract: "Curvature components derived from satellite gravity gradients provide new global views of Earth’s structure. The satellite gravity gradients are based on the GOCE satellite mission and we illustrate by curvature images how the Earth is seen differently compared to seismic imaging. Tectonic domains with similar seismic characteristic can exhibit distinct differences in satellite gravity gradients maps, which points to differences in the lithospheric build-up. This is particularly apparent for the cratonic regions of the Earth. The comparisons demonstrate that the combination of seismological, and satellite gravity gradient imaging has significant potential to enhance our knowledge of Earth’s structure. In remote frontiers like the Antarctic continent, where even basic knowledge of lithospheric scale features remains incomplete, the curvature images help unveil the heterogeneity in lithospheric structure, e.g. between the composite East Antarctic Craton and the West Antarctic Rift System."

Extract: "The gravity gradient findings show West Antarctica has a thinner crust and lithosphere compared to that of East Antarctica, which is made up of a mosaic of old cratons separated by younger orogens, revealing a family likeness to Australia and India.

These findings are of more than purely historic geological interest. They give clues to how Antarctica’s continental structure is influencing the behavior of ice sheets and how rapidly Antarctica regions will rebound in response to melting ice. "

Extract: "Knowing what lies beneath the ice sheet will help scientists understand its behavior and how the bedrock will respond as climate change begins melting the ice, causing the rock to rebound upward."

Not only will the Grace satellite data help to quantify West Antarctic bedrock rebound as ice mass is lost, but this tectonic information is useful for better understanding possible future responses of the West Antarctic Rift System, WARS, and its associated volcanoes (see the first image, and note that the extension of the WARS shoulder along the Antarctic Peninsula runs into the Shetland Plate). Furthermore, the second image shows the tectonic motion of the entire Antarctic tectonic plate on which the WARS rides and note the locations of the Shetland Plate and the Pacific/Australian Plate Boundary, relative to WARS. The third image shows that the WARS interconnects with the Ross Sea rift basins, which connect with the Balleny and Tasman Fracture Zones (in the Southern Ocean seafloor), which interconnect via a segment of mid-ocean ridge to the Macquarie Ridge Complex shown in the fourth attached image.

As a follow-on to my last post, the first image from the linked blog shows both a slightly positive stretching/compression ratio at both the east and west ends of the WARS over the past 250 million years.

Caption for the first image: "Total distributed continental deformation accumulated over 240 million years of rifting and crustal shortening. In Dietmar et al. (to come in 50th anniversary plate tectonics volume in Tectonics). A global plate model including lithospheric deformation along major rifts and orogens since the Triassic."

Caption for second image: "A) Ross Sea rift basins and Transantarctic Mountains are components of the West Antarctic Rift System (WARS-inset). Heat flow measurements made in the Victoria Land Basin are annotated and shown by white filled circles (see Table 1 for references). Within the Victoria Land Basin the Terror Rift, a 70-km-wide structure extending from Mt. Erebus to Mt. Melbourne, has been identified as the zone of most recent deformation (Cooper et al., 1987; Salvini et al., 1997). (B) Detailed map of Southern McMurdo Sound showing the location of the McMurdo Ice Shelf (MIS) drill hole AND-1B (yellow filled circle) and its heat flow value at the southern end of Terror Rift"

Furthermore, the following linked reference discusses the heat flow and rift basin system in the Ross Sea as determined by the ANDRILL study. The second image shows the relationship between the WARS and the Ross Sea rift and volcanic basins.

Abstract: "The Antarctic Drilling Program (ANDRILL) successfully drilled and cored a borehole, AND-1B, beneath the McMurdo Ice Shelf and into a flexural moat basin that surrounds Ross Island. Total drilling depth reached 1285 m below seafloor (mbsf) with 98 percent core recovery for the detailed study of glacier dynamics. With the goal of obtaining complementary information regarding heat flow and permeability, which is vital to understanding the nature of marine hydrogeologic systems, a succession of three temperature logs was recorded over a five-day span to monitor the gradual thermal recovery toward equilibrium conditions. These data were extrapolated to true, undisturbed temperatures, and they define a linear geothermal gradient of 76.7 K/km from the seafloor to 647 mbsf. Bulk thermal conductivities of the sedimentary rocks were derived from empirical mixing models and density measurements performed on core, and an average value of 1.5 W/mK ± 10 percent was determined. The corresponding estimate of heat flow at this site is 115 mW/m2. This value is relatively high but is consistent with other elevated heat-flow data associated with the Erebus Volcanic Province. Information regarding the origin and frequency of pathways for subsurface fluid flow is gleaned from drillers' records, complementary geophysical logs, and core descriptions. Only two prominent permeable zones are identified and these correspond to two markedly different features within the rift basin; one is a distinct lithostratigraphic subunit consisting of a thin lava flow and the other is a heavily fractured interval within a single thick subunit."

Finally, the third image shows a current overview of the West Antarctic tectonic systems, and I wonder what will happen if an abrupt collapse of the WAIS this century were to reactive both volcanoes and seismic activity in the WARS, and what that would do to the adjoining tectonic plate boundaries.

With a hat tip to solartim27 (from the Antarctic Tectonics thread, Reply #114), the first image shows that a newly identified lava lake has been found on Saunders Island, which is on the Sandwich Plate shown in the second image, which is next to the Scotia Plate, which is next to the Shetland Plate that is next to an extension of the WARS shoulder. Furthermore, the third image shows that most of the active volcanoes in the WARS exist along the WARS shoulder. Finally, the fourth image shows the relationship of the Alpine Fault (through New Zealand) West Antarctica and the Pangaea supercontinent some 280 million years ago. Hopefully, the WARS will not be reactivated as it was during and following the break-up of Pangaea:

Title: "Huge, rare and mysterious lava lake found in the Antarctic by British team"

In the last six years, five closely observed Antarctic glaciers have doubled their rate of ice loss, according to the National Science Foundation. At least one, Thwaites Glacier, modeled for the new study, may be in danger of succumbing to a hidden instability, likely to accelerate its flow into the ocean and push sea level up at a more rapid pace than previously expected.

How much ice the glacier will shed in coming 50 to 800 years can't exactly be projected due to unpredictable fluctuations in climate and the need for more data. But researchers at the Georgia Institute of Technology, NASA Jet Propulsion Laboratory, and the University of Washington have factored the instability into 500 ice flow simulations for Thwaites with refined calculations.

The scenarios diverged strongly from each other but together pointed to the eventual triggering of the instability, which will be described in the question and answer section below. Even if global warming were to later stop, the instability would keep pushing ice out to sea at an enormously accelerated rate over the coming centuries.

And this is if ice melt due to warming oceans does not get worse than it is today. The study went with present-day ice melt rates because the researchers were interested in the instability factor in itself.

"If you trigger this instability, you don't need to continue to force the ice sheet by cranking up temperatures. It will keep going by itself, and that's the worry,"... "After reaching the tipping point, Thwaites Glacier could lose all of its ice in a period of 150 years. That would make for a sea level rise of about half a meter (1.64 feet)." For comparison, current sea level is 20 cm (nearly 8 inches) above pre-global warming levels and is blamed for increased coastal flooding.

a) "Observation-based studies have typically found a smaller aerosol effective radiative forcing than in model simulations and were given preferential weighting in the IPCC AR5 report." &

b) "By showing a significant agreement between components of modelled and observational estimates of aerosol forcing, this study builds confidence in the global model estimates of the aerosol radiative forcing …"

c) "… this work suggests that model and observation-based estimates could be more equally weighted in future synthesis studies."

Thus, in effect it is recommending that future consensus scientist not bias their future reports (e.g. AR6) to under-report the relatively large negative aerosol effective radiative forcing projected by consensus climate models. Following this recommendation would force consensus climate scientists to acknowledge that climate sensitivity is more positive than AR5 indicates, and that as future anthropogenic aerosol emissions are reduced (say by switching from coal to natural gas usage) GMSTA will increase faster than projected by at least AR5:

Abstract. The radiative forcing from aerosols (particularly through their interaction with clouds) remains one of the most uncertain components of the human forcing of the climate. Observation-based studies have typically found a smaller aerosol effective radiative forcing than in model simulations and were given preferential weighting in the IPCC AR5 report. With their own sources of uncertainty, it is not clear that observation-based estimates are more reliable. Understanding the source of the model-observational difference is thus vital to reduce uncertainty in the impact of aerosols on the climate.

These reported discrepancies arise from the different decompositions of the aerosol forcing used in model and observational studies. Applying the observational decomposition to global climate model output, the two different lines of evidence are surprisingly similar, with a much better agreement on the magnitude of aerosol impacts on cloud properties. Cloud adjustments remain a significant source of uncertainty, particularly for ice clouds. However, they are consistent with the uncertainty from observation-based methods, with the liquid water path adjustment usually enhancing the Twomey effect by less than 50 %. Depending on different sets of assumptions, this work suggests that model and observation-based estimates could be more equally weighted in future synthesis studies.

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“It is not the strongest or the most intelligent who will survive but those who can best manage change.” ― Leon C. Megginson

The linked reference finds that w.r.t. organic carbon (OC) reserves in the subsea Arctic permafrost: "… current estimates of subsea OC substantially underestimate a major component of the global carbon cycle." While these Arctic subsea OC reserves do not include methane hydrates, as the current subsea permafrost continues to degrade, this will facilitate future releases of methane from subsea Arctic methane hydrates:

AbstractSea level rise after the Last Glacial Maximum (LGM) inundated several million square kilometers of Arctic permafrost, while estimates of organic carbon (OC) quantity and vulnerability to mineralization are exceedingly uncertain. We compiled geophysical measurements from Arctic continental shelves to estimate current subsea permafrost OC stocks. We found that marine transgression since the LGM inundated approximately 3.92×106 km2 of permafrost, which contained 1460±1010 Pg OC in the top 25 m of sediment. We estimated that current subsea permafrost underlies an area of 2.30×106 km2 and contains 860±590 Pg OC, not including methane hydrates. Most of the ~600 Pg of OC that thawed after the marine transgression is still present on the continental shelves. Although our estimates of subsea OC storage remain highly uncertain due to the sparse and uneven distribution of data, they suggest that current estimates of subsea OC substantially underestimate a major component of the global carbon cycle.

« Last Edit: July 09, 2019, 04:51:18 PM by AbruptSLR »

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“It is not the strongest or the most intelligent who will survive but those who can best manage change.” ― Leon C. Megginson

The linked reference indicates: "… a high potential for methane ebullition in the sediments of an Amazonian reservoir". As dams are increasingly being built in tropical zones, this research indicates the increasing risk of methane releases to the atmosphere from new tropical reservoirs, particularly around the inflow areas. This implies that consensus climate scientists have under estimated this source of future methane emissions:

Abstract. Reservoir sediments sequester significant amounts of organic carbon (OC), but at the same time, high amounts of methane (CH4) can be produced during the degradation of sediment OC. Hydropower is expanding in the Amazon basin, but the potential effects of river damming on the biogeochemistry of the Amazon river system can at present not be gauged due to a lack of studies. Here we present results from the first investigation of OC burial and CH4 concentrations in the sediments of an Amazonian reservoir. We performed sub-bottom profiling, sediment coring and sediment pore water analysis in the Curuá-Una reservoir (Amazon, Brazil) during rising and falling water periods. A mean sediment accumulation rate of 0.6 cm yr−1 and a mean OC burial rate of 91 g C m−2 yr−1 were found, which is the highest OC burial rate on record for low-latitude reservoirs, probably resulting from high OC deposition onto the sediment compensating for high OC mineralization at 28–30 °C water temperature. Elevated OC burial was found near the dam, and close to major river inflow areas. C : N ratios between 10.3 and 17 (mean ± SD: 12.9 ± 2.1) indicate that both land-derived and aquatic OC accumulate in CUN sediments. About 29 % of the sediment pore water samples had dissolved CH4 close to saturation concentration, a higher share than other hydroelectric reservoirs, indicating a high potential for CH4 ebullition, particularly in river inflow areas.

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“It is not the strongest or the most intelligent who will survive but those who can best manage change.” ― Leon C. Megginson

Abstract: "Recently, the Greenland Ice Sheet (GrIS) has become the main source of barystatic sea-level rise. The increase in the GrIS melt is linked to anticyclonic circulation anomalies, a reduction in cloud cover and enhanced warm-air advection. The Climate Model Intercomparison Project fifth phase (CMIP5) General Circulation Models (GCMs) do not capture recent circulation dynamics; therefore, regional climate models (RCMs) driven by GCMs still show significant uncertainties in future GrIS sea-level contribution, even within one emission scenario. Here, we use the RCM Modèle Atmosphèrique Règional to show that the modelled cloud water phase is the main source of disagreement among future GrIS melt projections. We show that, in the current climate, anticyclonic circulation results in more melting than under a neutral-circulation regime. However, we find that the GrIS longwave cloud radiative effect is extremely sensitive to the modelled cloud liquid-water path, which explains melt anomalies of +378 Gt yr–1 (+1.04 mm yr–1 global sea level equivalent) in a +2 °C-warmer climate with a neutral-circulation regime (equivalent to 21% more melt than under anticyclonic circulation). The discrepancies between modelled cloud properties within a high-emission scenario introduce larger uncertainties in projected melt volumes than the difference in melt between low- and high-emission scenarios."

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“It is not the strongest or the most intelligent who will survive but those who can best manage change.” ― Leon C. Megginson

Abstract Surface mass balance (SMB) provides mass input to the surface of the Antarctic and Greenland Ice Sheets and therefore comprises an important control on ice sheet mass balance and resulting contribution to global sea level change. As ice sheet SMB varies highly across multiple scales of space (meters to hundreds of kilometers) and time (hourly to decadal), it is notoriously challenging to observe and represent in models. In addition, SMB consists of multiple components, all of which depend on complex interactions between the atmosphere and the snow/ice surface, large‐scale atmospheric circulation and ocean conditions, and ice sheet topography. In this review, we present the state‐of‐the‐art knowledge and recent advances in ice sheet SMB observations and models, highlight current shortcomings, and propose future directions. Novel observational methods allow mapping SMB across larger areas, longer time periods, and/or at very high (subdaily) temporal frequency. As a recent observational breakthrough, cosmic ray counters provide direct estimates of SMB, circumventing the need for accurate snow density observations upon which many other techniques rely. Regional atmospheric climate models have drastically improved their simulation of ice sheet SMB in the last decade, thanks to the inclusion or improved representation of essential processes (e.g., clouds, blowing snow, and snow albedo), and by enhancing horizontal resolution (5–30 km). Future modeling efforts are required in improving Earth system models to match regional atmospheric climate model performance in simulating ice sheet SMB, and in reinforcing the efforts in developing statistical and dynamic downscaling to represent smaller‐scale SMB processes.Plain Language Summary Ice sheets, the largest class of glaciers, contain the majority of ice on Earth. The amount of ice contained in ice sheets changes constantly with the addition of new snow and ice, and melting taking place at the surface, base, and terminus of ice sheets. The balance between these inputs and outputs is known as the “mass balance.” Processes affecting the addition and removal of snow on top of the ice sheet are termed the “surface mass balance” and include rainfall, moisture evaporation, snow‐transporting winds, and melting due to temperature changes. Scientists can now monitor these processes with tools on‐site, such as automated weather stations, Global Positioning Systems, and sensors that record high‐energy radiation (cosmic rays) originating outside the Earth's atmosphere. Several methods are also available where Earth‐orbiting satellites measure how ice is changing. Data collected in these ways have revealed how the surface mass balance varies over time and space. A better understanding of these processes is critical to predicting future behavior of ice sheets and their effect on sea level. Improvements to regional‐scale models in the past decade have allowed good simulations of surface mass balance, and the next step is to build models that work at a global scale.

1 IntroductionEarth's ice sheets—the Greenland Ice Sheet (GrIS) in the Arctic and the Antarctic Ice Sheet (AIS) roughly centered around the South Pole—collectively contain more than two thirds of the planet's freshwater (Church et al., 2013). If melted completely, global mean sea level would be about 65 m higher than today (Alley et al., 2005). Observations show that both ice sheets are currently losing mass at accelerating rates (E. Rignot et al., 2011; Shepherd et al., 2012, 2018), in spite of large natural interannual variability. Even in a scenario of strong climate change mitigation, in which global mean temperature rise is limited to less than 2 °C relative to preindustrial values, ice sheets will continue to lose mass but are not likely to pass tipping points, in which case mass loss would become irreversible (Pattyn et al., 2018). In high‐emission scenarios, however, projected mass loss from the ice sheets becomes highly uncertain, especially for the AIS; some models predict AIS mass losses in excess of one meter of global sea level equivalent at the end of the 21st century, with multiple meters of potential additional sea level rise in the centuries thereafter (DeConto & Pollard, 2016).

Seeing as Earth may be headed towards PETM conditions, it is good to learn lessons from the past, and the linked article discusses a recent Smithsonian effort to reconstruct 500-million years of Earth's climate and they find that it can be really hard for life to adapt to abrupt climate change:

Extract: "Scott Wing and Brian Huber, a paleobotanist and paleontologist, respectively, at the museum, wanted to chart swings in Earth's average surface temperature over the past 500 million years or so. The two researchers also thought a temperature curve could counter climate contrarians' claim that global warming is no concern because Earth was much hotter millions of years ago. Wing and Huber wanted to show the reality of ancient temperature extremes—and how rapid shifts between them have led to mass extinctions. Abrupt climate changes, Wing says, "have catastrophic side effects that are really hard to adapt to.""

Keep in mind that there is near universal agreement among countries to strive the keep the future warming to 2 degrees C or less. There has been great progress in the deployment of carbon free power generation and transportation technologies and the transition is well underway. It would seem that we are far more likely to see future temperature increases of 1.5C to 2C than we are of seeing 5 to 8 C temperature increases.

Well it´s what we want to avoid but we should aim for certain instead of far more likely.

The countries are still letting the US and Saudi Arabia get away with BS at these summits. And we could just do so much more.

And despite all policies we already see that

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In western Antarctica, a glacier the size of Florida is losing ice faster than ever before. Sections of the Thwaites Glacier are retreating by up to 2,625 feet (800 metres) per year, contributing to 4 percent of sea-level rise worldwide.

That ice loss is part of a broader trend: The entire Antarctic ice sheet is melting nearly six times as fast as it did 40 years ago.

In the 1980s, Antarctica lost 40 billion tons of ice annually. In the last decade, that number jumped to an average of 252 billion tons per year.

Now, authors of a new study report that over the last six years, the rate at which five Antarctic glaciers slough off ice has doubled. That makes the Thwaites Glacier a melting time bomb.

Keep in mind that there is near universal agreement among countries to strive the keep the future warming to 2 degrees C or less. There has been great progress in the deployment of carbon free power generation and transportation technologies and the transition is well underway. It would seem that we are far more likely to see future temperature increases of 1.5C to 2C than we are of seeing 5 to 8 C temperature increases.

No offence but this sentiment seems to be coming from some alternate reality, one in which I would also much prefer to exist.

Keep in mind that there is near universal agreement among countries to strive the keep the future warming to 2 degrees C or less. There has been great progress in the deployment of carbon free power generation and transportation technologies and the transition is well underway. It would seem that we are far more likely to see future temperature increases of 1.5C to 2C than we are of seeing 5 to 8 C temperature increases.

No offence but this sentiment seems to be coming from some alternate reality, one in which I would also much prefer to exist.

I would have to agree, as the probability of staying under 2C is approaching zero given the lack of substantive action (i.e. significant cuts in GHG emissions) while research on positive feedbacks is increasing the probability of between 5 and 8C. Investment in renewables has fallen this year, with annual increases in renewable output not enough to reduce fossil fuel usage (oil, coal and gas),

Keep in mind that there is near universal agreement among countries to strive the keep the future warming to 2 degrees C or less. There has been great progress in the deployment of carbon free power generation and transportation technologies and the transition is well underway. It would seem that we are far more likely to see future temperature increases of 1.5C to 2C than we are of seeing 5 to 8 C temperature increases.

No offence but this sentiment seems to be coming from some alternate reality, one in which I would also much prefer to exist.

I would have to agree, as the probability of staying under 2C is approaching zero given the lack of substantive action (i.e. significant cuts in GHG emissions) while research on positive feedbacks is increasing the probability of between 5 and 8C. Investment in renewables has fallen this year, with annual increases in renewable output not enough to reduce fossil fuel usage (oil, coal and gas),

For the third year in a row, most leading indicators of coal powercapacity growth declined in 2018, including construction starts,pre-construction activity, and plant completions, according to theGlobal Coal Plant Tracker.1 In China and India, which have accountedfor 85% of new coal power capacity since 2005, the number of permitsfor new coal plants dropped to record lows. The level of coalplant retirements continued at a record pace, led primarily by the US,despite efforts by the Trump Administration to keep aging coal plantsonline.

And as the following scientific paper published in Nature this January indicates, the current fossil fuel infrastructure does not yet commit us to more than 1.5 C warming.

Committed warming describes how much future warming can be expected from historical emissions due to inertia in the climate system. It is usually defined in terms of the level of warming above the present for an abrupt halt of emissions. Owing to socioeconomic constraints, this situation is unlikely, so we focus on the committed warming from present-day fossil fuel assets. Here we show that if carbon-intensive infrastructure is phased out at the end of its design lifetime from the end of 2018, there is a 64% chance that peak global mean temperature rise remains below 1.5 °C. Delaying mitigation until 2030 considerably reduces the likelihood that 1.5 °C would be attainable even if the rate of fossil fuel retirement was accelerated. Although the challenges laid out by the Paris Agreement are daunting, we indicate 1.5 °C remains possible and is attainable with ambitious and immediate emission reduction across all sectors.

Renewables plus battery storage are now cheaper than operating coal and natural gas plants in the US, meaning many of those fossil fuel plants will be closed before the end of their useful lives. New fossil fuel plants wont be funded because renewables are cheaper. The following article just published in Science clearly illustrates this:

Giant batteries and cheap solar power are shoving fossil fuels off the grid

By Robert F. ServiceJul. 11, 2019 , 1:40 PM

This month, officials in Los Angeles, California, are expected to approve a deal that would make solar power cheaper than ever while also addressing its chief flaw: It works only when the sun shines. The deal calls for a huge solar farm backed up by one of the world's largest batteries. It would provide 7% of the city's electricity beginning in 2023 at a cost of 1.997 cents per kilowatt hour (kWh) for the solar power and 1.3 cents per kWh for the battery. That's cheaper than any power generated with fossil fuel.

"Goodnight #naturalgas, goodnight #coal, goodnight #nuclear," Mark Jacobson, an atmospheric scientist at Stanford University in Palo Alto, California, tweeted after news of the deal surfaced late last month. "Because of growing economies of scale, prices for renewables and batteries keep coming down," adds Jacobson, who has advised countries around the world on how to shift to 100% renewable electricity. As if on cue, last week a major U.S. coal company—West Virginia–based Revelation Energy LLC—filed for bankruptcy, the second in as many weeks.

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Precipitous price declines have already driven a shift toward renewables backed by battery storage. In March, an analysis of more than 7000 global storage projects by Bloomberg New Energy Finance reported that the cost of utility-scale lithium-ion batteries had fallen by 76% since 2012, and by 35% in just the past 18 months, to $187 per MWh. Another market watch firm, Navigant, predicts a further halving by 2030, to a price well below what 8minute has committed to.

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Local commitments to switch to 100% renewables are also propelling the rush toward grid-scale batteries. By Jacobson's count, 54 countries and eight U.S. states have required a transition to 100% renewable electricity. In 2010, California passed a mandate that the state's utilities install electricity storage equivalent to 2% of their peak electricity demand by 2024.

"Exceeding 1.5 °C occurs in only 9% of ensemble members under a zero emissions commitment if emissions cease at the end of 2018. Even if current fossil fuel infrastructure is retired at end of its lifetime and not replaced, it is possible to limit warming to 1.5 °C"

Neither of their scenarios relate to the real world, both from the increase in LNG and coal production and the record breaking production of shale oil in the US.

Local commitments to switch to 100% renewables are also propelling the rush toward grid-scale batteries. By Jacobson's count, 54 countries and eight U.S. states have required a transition to 100% renewable electricity. In 2010, California passed a mandate that the state's utilities install electricity storage equivalent to 2% of their peak electricity demand by 2024.

Natural gas has being taking over a lot of the US capacity, its going to be a good long while before renewable energy replaces it. This is new infrastructure.

"EIA expects the share of U.S. total utility-scale electricity generation from natural gas-fired power plants will rise from 35% in 2018 to 38% in 2019 and then decline slightly in 2020. EIA forecasts that the share of U.S. generation from coal will average 24% in 2019 and 23% in 2020, down from 27% in 2018. The forecast nuclear share of U.S. generation falls from 20% in 2019 to 19% in 2020, reflecting the retirement of reactors at five nuclear plants in 2019 and 2020. Hydropower averages a 7% share of total U.S. generation in the forecast for 2019 and 2020, similar to 2018. Wind, solar, and other nonhydropower renewables together provided 10% of U.S. total utility-scale generation in 2018. EIA expects they will provide 11% in 2019 and 13% in 2020."

Global emissions will continue to grow as more infrastructure is built out. 2018 had the highest ever emissions from energy related sources, the easy fix for emissions targets. That doesn't include the increase in petroleum usage in transportation and the increased pace of devastation of rain forest.

"Global energy-related CO2 emissions grew 1.7% in 2018 to reach a historic high of 33.1 Gt CO2. It was the highest rate of growth since 2013, and 70% higher than the average increase since 2010. Last year's growth of 560 Mt was equivalent to the total emissions from international aviation"

"Coal consumption grew by 1.4% in 2018, the fastest growth since 2013. This reverses a three-year period where coal either grew very little or actually declined, though global coal use still remains below its 2013 peak (see below for more)."

"Natural gas represented the single largest contributor to global energy-use growth in 2018, increasing by 5.3% compared to 2017. It alone was responsible for 40% of the increase in total energy use."

"Oil consumption grew by 1.5% in 2018, with China and the US contributing around 85% of the growth in oil use. This growth was primarily concentrated in the transportation sector, reflecting increased vehicle ownership and miles driven."

With the current governments in the US and Russia, Brazil. India isn't stopping production of coal plant infrastructure, 1.5°C is simply a pipe dream. We have to be cutting emissions, not increasing them, and renewable has simply no chance of keeping up the need for energy over the next decade, let alone starting to replace it.

With the current governments in the US and Russia, Brazil. India isn't stopping production of coal plant infrastructure, 1.5°C is simply a pipe dream. We have to be cutting emissions, not increasing them, and renewable has simply no chance of keeping up the need for energy over the next decade, let alone starting to replace it.

Renewables have only recently become less expensive than fossil fuel power plants, so much of the infrastructure that is coming online now was being planned five to ten years ago. New infrastructure being planned today wont be insured or financed as is currently the case with coal power. In the US, utilities are building new renewable power plants with the intent of shuttering coal or gas power plants years before the end of their operating lives, and they'll save money by doing it.

When Indiana's third-largest utility analyzed the economics of its power plants last year, it decided it was time for a big shift—away from the coal power that had long sustained the business and toward renewable energy.

The coal plants simply weren't paying off anymore. In fact, shutting them down would save about $4 billion over 30 years.

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Our conclusions were solely driven by economics and driving for more affordable rates for the state and ultimately for lower-cost energy for customers," Sistovaris said.

Utilities across the country have been coming to the same conclusion. This time it's in a Republican-leaning state with no renewable energy mandates.

And the science is clear that even with a small growth in emissions over the next few years, we can still limit warming with a transition to a low carbon economy.

The 2015 Paris Agreement calls for countries to pursue efforts to limit global-mean temperature rise to 1.5 °C. The transition pathways that can meet such a target have not, however, been extensively explored. Here we describe scenarios that limit end-of-century radiative forcing to 1.9 W/ m2, and consequently restrict median warming in the year 2100 to below 1.5 °C. We use six integrated assessment models and a simple climate model, under different socio-economic, technological and resource assumptions from five Shared Socio-economic Pathways (SSPs). Some, but not all, SSPs are amenable to pathways to 1.5 °C. Successful 1.9 W /m2 scenarios are characterized by a rapid shift away from traditional fossil-fuel use towards large-scale low-carbon energy supplies, reduced energy use, and carbon-dioxide removal. However, 1.9 W /m2 scenarios could not be achieved in several models under SSPs with strong inequalities, high baseline fossil-fuel use, or scattered short-term climate policy. Further research can help policy-makers to understand the real-world implications of these scenarios.

So I still argue that we're much more likely to limit the growth in temperatures to 2C or less than to see the 5 to 8C increase AbruptSLR is forecasting.

What would ´the completely accurate physics model of Earth´ show if we had that?

We rework datasets and discover that the situation is worse then we thought which reduces our budget in the real world. When we refine our understanding of ice melt all kinds of mechanisms come up which accelerate the warming.

Basically everything has been happening (a lot) quicker then predicted earlier from the nineties on.

Where will atlantification/pacification take us? Or the relentless Antarctic bottom melt. Even if we go zero tomorrow those things just keep on going.

Also remember we are not aiming for 2C because science tells us that that will save us. 1C would have been a much better target for that but the goalposts were moved because of lobbying because some people prefer destroying the world to giving up some current privilige.

In general this thread collects all kinds of science not in current IPCC reports so contrasting some of that with IPCC stuff is not really interesting...this is mostly a science thread which also mixes different subjects because of forum-historical reasons. There are enough threads in consequences where this subject pops up.

There is no such thing as a completely accurate model. Models are only as good as the tests they are subjected to.

We have observations that allow us to hindcast models to test them, to make sure they match the data that we have. That data is changing as our observations of the earth improve. Once we have a model that seems to be able to hindcast data then we can try to predict the future.

One problem with hindcasting is that it's easy to tweak the inputs to match the outcomes. However, if you make changes to the model that aren't back up by good theory, then it's basically data fitting the model. I haven't worked in climate modelling, but I would suspect that it's an easy trap to fall into as there are so many poorly defined parameters.

So I still argue that we're much more likely to limit the growth in temperatures to 2C or less than to see the 5 to 8C increase AbruptSLR is forecasting.

Well, we will have an answer soon, but the way that fossil fuel extraction has been increasing in 2019 coupled with the lack of clear government direction in the largest polluters. Extraction is accelerating.

I don't see any substantive change in emissions policy until 2021, and then you have had an extra trillion dollars or more of infrastructure built out. I would expect the ppm CO2 and fossil fuel usage to continue to INCREASE. We might see stronger policy start having an effect by 2025, as long as the democrats can stay in power. Gas and petroleum companies will NOT give up market dominance for power generation and transportation without incredibly strong policy. The market will simply no drive this. I know, I work in biofuels. Oil companies here are giving up $500m of credits so they don't have to blend biodiesel. They have lots of assets in the ground, and they will be making damn sure they get used to make the money out of them. There is enormous capped gas production capability in the US, the price will drop as pipelines are built out.

Los Angeles just announced the largest and cheapest solar+storage project in the world, but that's the golden land of dreamers and subsidies. About 1,800 miles to the right, conservative Indiana—with no renewable-portfolio standard—is making similar choices.

Renewables are so cheap, said Mike Hooper, the senior vice president of the Northern Indiana Service Company (NIPSCO), that the utility can close its coal plants early and return $4 billion to its customers over the next 30 years.

"It ends up being a really big number, somewhere in the neighborhood of $4 billion for our customers, and clearly a lot of that comes from the fact that there’s hundreds of millions of dollars in fuel every year from a marginal standpoint that you're not spending, that the customer gets the advantage of through the check they write us every month."

NIPSCO, which delivers power to the northern third of Indiana, issued a request for proposals in 2018 to transform its energy system away from coal. The company had issued a similar RFP in 2016, but the results it got this time were markedly different.

"We kind of made an assumption that as the results came back it would be very much similar to 2016, particularly where we sit in the world, that natural-gas generation would be the most cost-effective option," Hooper said. "And as we ran this RFP and got our results back, we were surprised to see that wind—especially early wind in service in 2020 and 2021—and then solar, on a levelized-cost-of-energy-basis, were significantly less expensive than new gas-fired generation."

In the USA, money talks. And money is now firmly behind renewables. Coal is dead and natural gas isn't far behind.

So you can run all the model runs at RCP8.5 that you want to and talk about BAU scenarios, but those days are over.

And that is all policy/economics so there are better threads to discuss that in policy/solutions or consequences and it is arguably more important for third party readers to discuss there which scenarios are likely...ASLR posts a lot of rather technical stuff so it is not the stuff newbies read up on first i guess (i was not a real newbie when.

The main readers/participants on this thread are not interested in what IPCC cobbled together in the past but we are interested new papers on the bounds of the budget (revised historical temp sets) , newly discovered real world processes that are not modelled and new paleo evidence or examples of where models and paleo evidence cannot easily be reconciled.

So just keep posting the good news stuff in the above mentioned forums. I appreciate the articles there and left many a like on them.

Transport will keep oil in demand for decades to come. Electric Vehicles have come a long way in the last 20 years but I still feel like it will be 20 more years until they have a significant impact. It's all about the batteries. I'd love to buy an EV but the initial purchase price is still close to double what you need to pay for a diesel or petrol engine vehicle.

I did read an article a few years ago now, about the research into extract the suitable hydrocarbons from plants. Not just talking about bio-diesel. This research was being funded by airline companies who were as much concerned about the quality of fuel they get from oil companies as they were about CO2.

« Last Edit: July 14, 2019, 04:36:39 AM by Stephen »

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The ice was here, the ice was there, The ice was all around:It crack'd and growl'd, and roar'd and howl'd, Like noises in a swound!Rime of the Ancient Mariner by Samuel Taylor Coleridge

Extract: "The Arctic is on fire. Dozens of wildfires of an unprecedented intensity have been burning across the Arctic circle for the past few weeks, releasing as much CO2 in just one month as Sweden’s total annual emissions.

Fires in the region are not unknown but the scale of the blazes, predominantly in boreal peatlands across Siberia, is surprising. Satellite measurements show the amount of energy released by the fires in June is more than that released by all the previous nine years …"

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“It is not the strongest or the most intelligent who will survive but those who can best manage change.” ― Leon C. Megginson

Extract: "“Scientists are talking about an intense mix of emotions right now,” says Christine Arena, executive producer of the docuseries Let Science Speak, which featured climate researchers speaking out against efforts to silence or ignore science. “There’s deep grief and anxiety for what’s being lost, followed by rage at continued political inaction, and finally hope that we can indeed solve this challenge. There are definitely tears and trembling voices. They know this deep truth: They are on the front lines of contending with the fear, anger, and perhaps even panic the rest of us will have to deal with.”"

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“It is not the strongest or the most intelligent who will survive but those who can best manage change.” ― Leon C. Megginson

A new model from MIT indicates that previous consensus climate models have underestimated the atmospheric CO2 levels required to push the ocean beyond a tipping point that would lead to mass extinction in the coming millenia:

Extract: "Daniel Rothman, professor of geophysics and co-director of the Lorenz Center in MIT’s Department of Earth, Atmospheric and Planetary Sciences, has found that when the rate at which carbon dioxide enters the oceans pushes past a certain threshold — whether as the result of a sudden burst or a slow, steady influx — the Earth may respond with a runaway cascade of chemical feedbacks, leading to extreme ocean acidification that dramatically amplifies the effects of the original trigger.

This global reflex causes huge changes in the amount of carbon contained in the Earth’s oceans, and geologists can see evidence of these changes in layers of sediments preserved over hundreds of millions of years.

Rothman looked through these geologic records and observed that over the last 540 million years, the ocean’s store of carbon changed abruptly, then recovered, dozens of times in a fashion similar to the abrupt nature of a neuron spike. This “excitation” of the carbon cycle occurred most dramatically near the time of four of the five great mass extinctions in Earth’s history.…What does this all have to do with our modern-day climate? Today’s oceans are absorbing carbon about an order of magnitude faster than the worst case in the geologic record — the end-Permian extinction. But humans have only been pumping carbon dioxide into the atmosphere for hundreds of years, versus the tens of thousands of years or more that it took for volcanic eruptions or other disturbances to trigger the great environmental disruptions of the past. Might the modern increase of carbon be too brief to excite a major disruption?

According to Rothman, today we are “at the precipice of excitation,” and if it occurs, the resulting spike — as evidenced through ocean acidification, species die-offs, and more — is likely to be similar to past global catastrophes.…“We already know that our CO2-emitting actions will have consequences for many millennia,” says Timothy Lenton, professor of climate change and earth systems science at the University of Exeter. “This study suggests those consequences could be much more dramatic than previously expected. If we push the Earth system too far, then it takes over and determines its own response — past that point there will be little we can do about it.”"

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“It is not the strongest or the most intelligent who will survive but those who can best manage change.” ― Leon C. Megginson

SignificanceOngoing permafrost thaw is expected to stimulate microbial release of greenhouse gases, threatening to further exacerbate climate change (cause positive feedback). In this study, a unique field warming experiment was conducted in Interior Alaska to promote surface permafrost degradation while maintaining uniform hydraulic conditions. After 5 winters of experimental warming by ∼1 °C, microbial community shifts were observed at the receded permafrost/active layer boundary, which reflected more reduced conditions, including increased methanogenesis. In contrast, increased carbohydrate utilization (respiration) was observed at the surface layer. These shifts were relatable to observed increases in CO2 and CH4 release from this study site and the surrounding ecosystem. Collectively, our results demonstrate that microbial responses to warming are rapid and identify potential biomarkers that could be important in modeling.

AbstractNorthern-latitude tundra soils harbor substantial carbon (C) stocks that are highly susceptible to microbial degradation with rising global temperatures. Understanding the magnitude and direction (e.g., C release or sequestration) of the microbial responses to warming is necessary to accurately model climate change. In this study, Alaskan tundra soils were subjected to experimental in situ warming by ∼1.1 °C above ambient temperature, and the microbial communities were evaluated using metagenomics after 4.5 years, at 2 depths: 15 to 25 cm (active layer at outset of the experiment) and 45 to 55 cm (transition zone at the permafrost/active layer boundary at the outset of the experiment). In contrast to small or insignificant shifts after 1.5 years of warming, 4.5 years of warming resulted in significant changes to the abundances of functional traits and the corresponding taxa relative to control plots (no warming), and microbial shifts differed qualitatively between the two soil depths. At 15 to 25 cm, increased abundances of carbohydrate utilization genes were observed that correlated with (increased) measured ecosystem carbon respiration. At the 45- to 55-cm layer, increased methanogenesis potential was observed, which corresponded with a 3-fold increase in abundance of a single archaeal clade of the Methanosarcinales order, increased annual thaw duration (45.3 vs. 79.3 days), and increased CH4 emissions. Collectively, these data demonstrate that the microbial responses to warming in tundra soil are rapid and markedly different between the 2 critical soil layers evaluated, and identify potential biomarkers for the corresponding microbial processes that could be important in modeling.

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“It is not the strongest or the most intelligent who will survive but those who can best manage change.” ― Leon C. Megginson

"Natural gas exports are on the cusp of growing significantly, both to Mexico and as LNG to markets around the globe. Further, low gas prices have fostered growth in the power generation market as coal and nuclear plants continue to be retired across the U.S. This trend seems irreversible considering regulations that encourage clean power and the way in which gas complements renewables. Regardless of policies, the relatively low gas price environment generally discourages additional investment to upgrade or further limit emissions from coal plants, especially considering the threat of federal carbon control that still looms on the horizon.The scenarios in this study project significant growth in oil and gas production and markets that stimulate such growth. U.S. and Canadian oil production increases to over 19 million barrels per day by 2035. Natural gas production growth is even more pronounced, increasing from roughly 91 billion cubic feet per day in 2017 to 130 billion cubic feet per day by 2035. NGL production will track gas production over time."

While methane emissions from past, present and projected future human bodies, is a minor source of GHG in the atmosphere, it is still interesting to note that it is increasing nonlinearly through at least 2100:

Abstract: "Methane (CH4) is a potent greenhouse gas released to the atmosphere by various natural and anthropogenic sources. Numerous studies have been conducted to quantify the major and minor CH4 sources on spatial and temporal time scales. A minor source of the atmospheric global CH4 budget is the direct release of CH4 from the living human body. Based on available data from recent publications, for the first time, CH4 emissions from human breath and flatus are estimated on a global scale taking into account dominant factors influencing emission, such as age, ethnicity, and gender. Human CH4 emissions are compared between preindustrial times (1750), present age (2017) and future prediction (2100) using demographic data based on World Population Prospects 2017 of the United Nations (UN 2017). In preindustrial times the global CH4 release by humans is estimated at 34 ± 28 Gg and then substantially increase by a factor of ten reaching 344 ± 255 Gg by 2017. Emissions are estimated to further increase by almost fourfold to a value of 1221 ± 672 Gg by 2100, even though the rise in population is predicted to only increase by 50%. This nonlinear relationship is related to the predicted change in population structure affecting the number of CH4 producers. In contrast, for the year 2100 the simplified non-weighted estimation which merely considers the expected increase in population would only account for 612 ± 169 Gg. The discrepancy between the simplified non-weighted and weighted estimations of human CH4 emissions emphasises the importance of factor-based calculations in order to compile more accurate data."

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“It is not the strongest or the most intelligent who will survive but those who can best manage change.” ― Leon C. Megginson

While methane emissions from past, present and projected future human bodies, is a minor source of GHG in the atmosphere, it is still interesting to note that it is increasing nonlinearly through at least 2100:

Methane from farts is increasing faster than human population rise alone would indicate. While the article does not speculate on the reasons for increased fartification, it does point to the importance of considering all factors when assessing fart rates.

he Tropical Pacific telecommunicates heat energy through the atmosphere to West Antarctica partially depending of ENSO conditions as indicated by the attached image, and the linked reference finds that: "… ENSO activity and its influence on Antarctic temperature are increasing in response to increasing radiative GHG forcing since the industrial era." This indicates that the WAIS may sustain more ice mass loss, with continuing global warming, than previously assumed by consensus climate science:

Abstract: "Under the influence of recent global warming, modulation of frequencies and amplitude of El Niño-Southern Oscillation (ENSO) and its impacts on global climate have become great concerns to the global community. Antarctic climate is sensitive to these changes owing to tropical and Southern Hemispheric (SH) teleconnections. Antarctic surface air temperature (SAT) reconstructed approximately for the past five centuries (~1533 to 1993 CE) based on multiple oxygen isotope (δ18O) records of ice cores from East and West Antarctica show dominant oscillations in ENSO and Pacific Decadal Oscillation (PDO) frequency bands. Further, variance of the East Antarctica (EA) temperature record shows significant increasing trend at ENSO band and decreasing trend at PDO band since the industrial era (~1850 CE). This observation is consistent with the earlier report of increasing ENSO activity, reconstructed based on tropical-subtropical tree ring records. ENSO influence in the SH high-latitude is known to be characterized by Pacific South American (PSA) pattern reflected in the atmospheric pressure fields. Our investigation of greenhouse gas (GHG) forced model simulation results show an increasing trend in PSA activity since the industrial era. Thus, we suggest ENSO activity and its influence on Antarctic temperature are increasing in response to increasing radiative GHG forcing since the industrial era."

The authors of the linked reference are experts in 'transient climate response to cumulative CO2 emissions' (TCRE), and their research helps to identify a path forward to the remaining 'carbon budget' (which might have a negative value depending on assumptions). Unfortunately, these TCRE experts do not even mention ice-climate feedback mechanisms (including those explicitly cited in peer reviewed references); so it is clear that these experts are still erring on the side of least drama:

Abstract: "Research reported during the past decade has shown that global warming is roughly proportional to the total amount of carbon dioxide released into the atmosphere. This makes it possible to estimate the remaining carbon budget: the total amount of anthropogenic carbon dioxide that can still be emitted into the atmosphere while holding the global average temperature increase to the limit set by the Paris Agreement. However, a wide range of estimates for the remaining carbon budget has been reported, reducing the effectiveness of the remaining carbon budget as a means of setting emission reduction targets that are consistent with the Paris Agreement. Here we present a framework that enables us to track estimates of the remaining carbon budget and to understand how these estimates can improve over time as scientific knowledge advances. We propose that application of this framework may help to reconcile differences between estimates of the remaining carbon budget and may provide a basis for reducing uncertainty in the range of future estimates."

See also:Title: "Guest post: A new approach for understanding the remaining carbon budget"

"Putting all these factors together and taking into account emissions since 2011 then results in a remaining carbon budget from 2018 onwards of 580GtCO2 for a 50% chance of keeping warming below 1.5C. This is less than 15 years of global emissions at current rates.

So, what does that mean?

This means that if we start reducing emissions steeply now and by the time we reach net-zero levels we have not emitted more than 580GtCO2, our best scientific understanding tells us have we expect a one-in-two chance that warming would be kept to 1.5C.

Moreover, if we want to be sure that this is also true until the end of the century, we’d have to aim to emit only 480GtCO2 until we reach net-zero instead. This is under 12 years of current emissions."

The linked reference uses a Green's function approach to demonstrate that the projected SST warming pattern for the Tropical Pacific will lead to increasing values of climate sensitivity in the coming decades:

Yue Dong et al. (2019), "Attributing Historical and Future Evolution of Radiative Feedbacks to Regional Warming Patterns using a Green’s Function Approach: The Preeminence of the Western Pacific", Journal of Climate, https://doi.org/10.1175/JCLI-D-18-0843.1

https://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-18-0843.1AbstractGlobal radiative feedbacks have been found to vary in global climate model (GCM) simulations. Atmospheric GCMs (AGCMs) driven with historical patterns of sea-surface temperatures (SST) and sea-ice concentrations produce radiative feedbacks that trend toward more negative values, implying low climate sensitivity, over recent decades. Freely-evolving coupled GCMs driven by increasing CO2 produce radiative feedbacks that trend toward more positive values, implying increasing climate sensitivity, in the future. While this time-variation in feedbacks has been linked to evolving SST patterns, the role of particular regions has not been quantified. Here, a Green’s function is derived from a suite of simulations within an AGCM (NCAR’s CAM4), allowing an attribution of global feedback changes to surface warming in each region.

The results highlight the radiative response to surface warming in ascent regions of the western tropical Pacific as the dominant control on global radiative feedback changes. Historical warming from the 1950s to 2000s preferentially occurred in the western Pacific, yielding a strong global outgoing radiative response at the top of atmosphere (TOA) and thus a strongly negative global feedback. Long-term warming in coupled GCMs occurs preferentially in tropical descent regions and in high latitudes, where surface warming yields small global TOA radiation change but large global surface air temperature change, and thus a less-negative global feedback. These results illuminate the importance of determining mechanisms of warm pool warming for understanding how feedbacks have varied historically and will evolve in the future.

« Last Edit: July 19, 2019, 05:49:50 PM by AbruptSLR »

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“It is not the strongest or the most intelligent who will survive but those who can best manage change.” ― Leon C. Megginson

... our best scientific understanding tells us have we expect a one-in-two chance that warming would be kept to 1.5C.

First, in my opinion Rogelj et al. (2019)'s finding represent the best consensus scientific understanding, not the best scientific understanding.

Second, focusing too much on the annual global mean surface temperature anomaly, GMSTA, ignores the fact that climate variability is also increasing with continuing global warming, and that large fluctuations in radiative forcing (say a particularly warm monthly GMSTA, see attached image for the month of June thru 2019) could trigger various positive feedback mechanisms [which could increase ECS faster than Rogelj et al. (2019) assume]:

As a follow-on to my last post (that confirms that June 2019 had the largest GMSTA for any June in modern times), I attach Gavin Schmidt's projection for the annual 2019 GISTEMP based on data thru June 2019; which indicates that GMSTA in 2019 most likely will not be the warmest on record (but will be one of the warmest years on record):

The public is so hungry for a magic bullet (or technical savior) to the climate change threat that the media tends to pander to this hunger, such as the press coverage of Bastin et al. (2019), while ignoring important feedback mechanisms, as discussed in the linked article. Even though planting a reasonable number of trees is generally a good idea; promoting the idea that planting trees alone can solve our current situation is not a good idea:

Extract: "In recent weeks, a new study by researchers at ETH Zurich has hit the headlines worldwide (Bastin et al. 2019). It is about trees. The researchers asked themselves the question: how much carbon could we store if we planted trees everywhere in the world where the land is not already used for agriculture or cities? Since the leaves of trees extract carbon in the form of carbon dioxide – CO2 – from the air and then release the oxygen – O2 – again, this is a great climate protection measure. The researchers estimated 200 billion tons of carbon could be stored in this way – provided we plant over a trillion trees.

The media impact of the new study was mainly based on the statement in the ETH press release that planting trees could offset two thirds of the man-made CO2 increase in the atmosphere to date. To be able to largely compensate for the consequences of more than two centuries of industrial development with such a simple and hardly controversial measure – that sounds like a dream! And it was immediately welcomed by those who still dream of climate mitigation that doesn’t hurt anyone.

Unfortunately, it’s also too good to be true. Because apples are compared to oranges and important feedbacks in the Earth system are forgotten.…There is another problem that the authors do not mention: a considerable part of the lands eligible for planting are in the far north in Alaska, Canada, Finland and Siberia. Although it is possible to store carbon there with trees, albeit very slowly, this would be counterproductive for the climate. For in snowy regions, forests are much darker than snow-covered unwooded areas. While the latter reflect a lot of solar radiation back into space, the forests absorb it and thus increase global warming instead of reducing it (Bala et al. 2007, Perugini et al. 2017). And increased regional warming of the Arctic permafrost areas in particular would be a terrible mistake: permafrost contains more carbon than all trees on earth together, around 1,400 GtC. We’d be fools to wake this sleeping giant.…The study by the ETH researchers has another important result that has hardly been reported. Without effective climate protection, progressive warming will lead to a massive loss of existing forest cover, especially in the tropics. At the same time, the models are not yet able to make reliable statements on how forests can cope with new extremes, fire, thawing permafrost, insects, fungi and diseases in a changing climate."

As a follow-on to my last post (that confirms that June 2019 had the largest GMSTA for any June in modern times), I attach Gavin Schmidt's projection for the annual 2019 GISTEMP based on data thru June 2019; which indicates that GMSTA in 2019 most likely will not be the warmest on record (but will be one of the warmest years on record):

Extract: "Deforestation in Brazil’s portion of the Amazon rainforest rose more than 88% in June compared with the same month a year ago, the second consecutive month of rising forest destruction under the rightwing president Jair Bolsonaro.

Extract: "Bark beetles are currently responsible for killing an unprecedented number of trees in forests across Europe and North America. Why the beetle populations first explode to decline naturally after a few years is largely unknown. Researchers are therefore urging to step up research into the dynamics of bark beetle populations. They believe that more needs to be done also in view of climate change."

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“It is not the strongest or the most intelligent who will survive but those who can best manage change.” ― Leon C. Megginson